The present invention relates generally to passenger restraint systems and, more particularly, to safety belt retractors of the type used in vehicular seating applications.
Virtually all motor vehicles are now equipped with safety belt restraint systems for physically restraining the seat occupants when the vehicle is subjected to a high rate of deceleration which may occur, for example, during a motor vehicle collision. Traditionally, safety belt restraint systems include one of more rotary-type safety belt retractors which function to normally permit the belt webbing to be controllably withdrawn and retracted from a spring-biased spool assembly. It is also known to provide such rotary-type belt retractors with a locking mechanism that is selectively actuated in response to the occurrence of a predetermined event (i.e., latching of the belt buckle, vehicular deceleration forces above a maximum level, etc.) for preventing subsequent withdrawal of belt webbing, thereby restraining the seat occupant.
While conventional safety belt restraint systems are well-suited for restraining adult passengers, it is a common practice to use an auxiliary child seat having a belt-type harness restraint for children under a given age and weight. As is known, the child seat is placed on top of the vehicle seat and is secured thereto using the existing vehicular safety belt restraint system. It is also known to incorporate the aforementioned rotary-type belt retractor into the auxiliary child seat for preventing withdrawal of the harness restraint once the child is fastened therein. An example of such a locking arrangement for an auxiliary child seat is disclosed in U.S. Pat. No. 4,720,148.
In an effort to minimize the inconvenience associated with installing and/or stowing auxiliary child seats, some motor vehicles are now available with seating arrangements having one or more "fold-out" or integral child seats incorporated into the backrest of an otherwise conventional seat. Typically, such seating arrangements are adapted to accommodate an adult in a normal seated position when the integral child seat is stowed within the backrest. When needed, the integral child seat can be easily deployed to expose a belt-type harness restraint similar to that used with auxiliary child seats. Moreover, it is also common to incorporate a "tightening" mechanism into the integral child seat for adjusting the tension exerted on the child by the harness restraint. One commercially-available integral child seat employs a cinch-type belt tightening mechanism that can be manually-operated for adjusting the circuitous length of the harness restraint.
As an alternative to conventional cinch-type belt tightening devices, it is highly desireable to provide a "automatic" belt tightening mechanism which is operable for exerting a retractive force on the harness restraint while preventing withdrawal thereof in response to the child being buckled into the harness restraint. Such an automatic belt tightening mechanism offers greater convenience to the user, since no separate adjustment operations are required. Thus, it has been proposed to incorporate a conventional rotary-type belt retractor into an integral child seat for use as an automatic belt tightening mechanism. Unfortunately, in view of the need to provide comfort to adult seat occupants and preserve the overall cosmetic appearance of the seating arrangement when the integral child seat is in the stowed position, the available space for mounting such a conventional rotary-type belt retractor is severely limited.